Jacobs Vehicle Systems has introduced its Fulcrum Bridge technology to the off-highway market. Jacobs says the technology eliminates the need to periodically adjust an engine’s lash settings, making conventional engine braking compatible for the first time with lashless technology.
Jacobs says that its Fulcrum Bridge removes the traditional need to set and adjust the mechanical clearance in the valve train between valve and camshaft, known as lash, by employing Hydraulic Lash Adjusters (HLA). Hydraulic lash adjustment allows for more consistent valve motions throughout all engine operating conditions and wear over the engine lifetime, enhancing engine performance and fuel economy, Jacobs says.
HLA technology has advantages for engine manufacturers because setting lash on engine assembly lines can cause bottlenecks, and advantages for engine operators as they benefit from a reduction in vehicle downtime because the need to check and adjust lash is eliminated for intake and exhaust main events. This servicing requirement can be especially inconvenient where engines are in use in specialty off-highway applications because a clean environment is needed when accessing the overhead and opening the valve cover, and when getting access to the engine may require significant vehicle disassembly.
Another disadvantage of traditional, manually-adjustable lash is that the adjustments are often set with slight inaccuracies, with a detrimental effect on exhaust emissions and fuel consumption. Variance from the optimum setting by as little as 0.01 cm may be enough to negatively affect engine breathing and efficiency, Jacobs says.